Core A: Mouse Coagulation Laboratory The Mouse Coagulation Laboratory has been developed as Core A for this PPG to serve each of the investigators in this program with procoagulation, fibrinolysis, and anticoagulation testing of mouse samples. These assays have been established for a number of mouse lines. In addition to established functional assays for mouse proteins, immunochemical assays for various mouse proteins will be developed for a panel of coagulation factors central to the proposed studies of all 4 PPG projects. It is the goal of this funding period to develop antigens assays for mouse activated products of coagulation. The specific aims of the Mouse Coagulation Laboratory are as follows: Specific Aim #1 : Core A will provide FV activity and antigen, APCR, TFPI activity, D-Dimer, thrombin- antithrombin complex, and prothrombin fragment 1+2 assays for Project #1. Specific Aim #2: Core A will measure FVIII:C activity and antigen of human rFVIII:C infused into FVIII:C null mice in pharmacokinetic studies, mouse vWF activity & antigen, and provide Rose Bengal thrombosis studies and plasma protein analysis of mice made prothrombotic by human FVIII:C infusion for Project #2. Specific Aim #3: Core A will provide tPA and PAl-1 activity and antigen assays, tissue factor activity, vitronectin antigen, and cholesterol assays for the investigators of Projects #3 and #4. It is intended that the services of Core A will be used by all of the individual projects contained in the PPG. Significant gains in economy, efficiency and accuracy will be achieved by centralizing the resources of this laboratory in one location. Dr. Alvin H. Schmaier, Director of the Coagulation Laboratory at the University of Michigan Hospitals will be overall director of this Core. He will also coordinate all work at the University of Michigan and the development of novel antigen assays for the coagulation proteins needed by the PPG investigators listed above at the subcontract, Specialty Laboratories, Santa Monica CA.